<script setup>
import { useMouseInElement } from '@vueuse/core'
import { ref, watch } from 'vue'

const props = defineProps({
  imageList: Array,
  default: () => []
})

// 图片列表
// const imageList = props.value.imageList

// 小图切换大图展示
const imgIndex = ref(0)

const onMouseenter = (i) => {
    // console.log('鼠标滑动到底' + i + '个小图标')
    imgIndex.value = i
}

// 获取鼠标相对位置
const target = ref()
const left = ref(0)
const top = ref(0)
const positionX = ref(0)
const positionY = ref(0)
const { elementX, elementY, isOutside } = useMouseInElement(target)

// 控制滑块跟鼠标移动，监控elementX/Y变化
watch([elementX, elementY, isOutside], () =>{
  if ( isOutside.value ) return
  // 横向
  if (elementX.value > 100 && elementX.value < 300 ) {
    left.value = elementX.value -100
  }
  // 纵向
  if (elementY.value > 100 && elementY.value <300 ) {
    top.value = elementY.value -100
  }
  // 处理边界
  if ( elementX.value > 300 ) { left.value = 200 }
  if ( elementX.value < 100 ) { left.value = 0 }
  if ( elementY.value > 300 ) { top.value = 200 }
  if ( elementY.value < 100 ) { top.value = 0 }

  positionX.value = left.value * -2
  positionY.value = top.value * -2
})

</script>


<template>
  <!-- {{ elementX }},{{ elementY }},{{ isOutside }} -->
  <div class="goods-image">
    <!-- 左侧大图-->
    <div class="middle" ref="target">
      <img :src="imageList[imgIndex]" alt="" />
      <!-- 蒙层小滑块 -->
      <div v-show="!isOutside" class="layer" :style="{ left: `${ left }px`, top: `${ top }px` }"></div>
    </div>
    <!-- 小图列表 -->
    <ul class="small">
      <li v-for="(img, i) in imageList" :key="i" @mouseenter="onMouseenter(i)" :class="{active : i === imgIndex}">
        <img :src="img" alt="" />
      </li>
    </ul>
    <!-- 放大镜大图 -->
    <div class="large" :style="[
      {
        backgroundImage: `url(${imageList[imgIndex]})`,
        backgroundPositionX: `${ positionX }px`,
        backgroundPositionY: `${ positionY }px`,
      },
    ]" v-show="!isOutside"></div>
  </div>
</template>

<style scoped lang="scss">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
  }

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    z-index: 500;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    // 背景图:盒子的大小 = 2:1  将来控制背景图的移动来实现放大的效果查看 background-position
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }

  .layer {
    width: 200px;
    height: 200px;
    background: rgba(0, 0, 0, 0.2);
    // 绝对定位 然后跟随咱们鼠标控制left和top属性就可以让滑块移动起来
    left: 0;
    top: 0;
    position: absolute;
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid $xtxColor;
      }
    }
  }
}
</style>